In communications networks, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications network is deployed.
For example, for future generations of mobile communications systems frequency bands at many different carrier frequencies could be needed. For example, low such frequency bands could be needed to achieve sufficient network coverage for wireless radio transceiver devices and higher frequency bands (e.g. at millimeter wavelengths (mmW), i.e. near and above 30 GHz) could be needed to reach required network capacity. In general terms, at high frequencies the propagation properties of the radio channel are more challenging and beamforming both at the access node of the network and at the wireless radio transceiver devices might be required to reach a sufficient link budget.
The wireless radio transceiver devices could implement beamforming by means of analog beamforming, digital beamforming, or hybrid beamforming. Each implementation has its advantages and disadvantages. A digital beamforming implementation is the most flexible implementation of the three but also the costliest due to the large number of required radio chains and baseband chains. An analog beamforming implementation is the least flexible but cheaper to manufacture due to a reduced number of radio chains and baseband chains compared to the digital beamforming implementation. A hybrid beamforming implementation is a compromise between the analog and the digital beamforming implementations. As the skilled person understands, depending on cost and performance requirements of different wireless radio transceiver devices, different implementations will be needed.
When the wireless radio transceiver devices uses analog beamforming it could be challenging for the wireless radio transceiver devices to determine if a currently used beam produced by using the analog beamforming is a good beam in terms of a given signal quality criterion or if there exist other beams that if generated by the analog beamforming would perform significantly better in terms of the given signal quality criterion. In order to evaluate if any other such beam is better a beam finding procedures, for example using beam reference signals (BRS), could be used. However, performing such a procedure typically requires comparatively much overhead signaling between the access node and the wireless radio transceiver device which, thus, will temporarily occupy radio resources and increase the average interference in the network.
Hence, there is a need for an improved beam finding procedure.